While numerous studies are available on methane pyrolysis chemical kinetics and the effect of plasma parameters on graphene synthesis, a comprehensive understanding of the formation mechanism remains elusive without in situ analysis. This study aims to utilize a sampling probe for the first time to collect graphene locally on transmission electron microscopy grids and perform a localized sampling and analysis of the gas composition (during graphene synthesis) using mass spectrometry. This technique provides a 3D tracking of methane pyrolysis in radiofrequency inductively coupled thermal plasma reactor for graphene production. Response surface methodology based on central composite design is employed to obtain a 3D visualization of the synthesis process. Quadratic and cubic models are developed, followed by comprehensive analysis of variance. A comparison of the gas-phase chemistry resulting from the in situ measurements with thermodynamic equilibrium calculations reveals that the process is controlled by thermochemical kinetics. H₂, C₂H₂, C₂H₄, C₃H_6, and C₆H_6, as well as residual CH₄, are the main hydrocarbons found in the graphene nucleation zone. The primary pathway for methane pyrolysis and graphene formation in RF plasma is through H₂ and C₂ hydrocarbons, while graphene nucleation and growth reactions are terminated 350 mm from the plasma torch nozzle exit. Morphology, quality, mean particle size, and the number of layers of the produced graphene samples, locally collected at different locations by 3D axisymmetric probe scanning, were investigated using TEM, high-resolution TEM imaging, and Raman analysis. The gathered information is highly valuable for plasma reactor design.

虽然对甲烷热解化学动力学和等离子体参数对石墨烯合成的影响进行了大量研究，但如果不进行原位分析，对形成机制的全面了解仍然难以实现。本研究旨在首次利用采样探针在透射电子显微镜网格上局部收集石墨烯，并使用质谱法对气体成分（在石墨烯合成过程中）进行局部采样和分析。该技术提供了用于石墨烯生产的射频感应耦合热等离子体反应器中甲烷热解的 3D 跟踪。采用基于中心复合设计的响应面方法来获得合成过程的 3D 可视化。开发二次和三次模型，然后进行方差的综合分析。将原位测量产生的气相化学与热力学平衡计算进行比较表明，该过程是由热化学动力学控制的。H ₂、C ₂ H ₂、C ₂ H ₄、C ₃ H ₆和C ₆ H ₆以及残留的CH ₄是石墨烯成核区中发现的主要碳氢化合物。RF等离子体中甲烷热解和石墨烯形成的主要途径是通过H ₂和C ₂烃，而石墨烯成核和生长反应在距等离子体炬喷嘴出口350mm处终止。使用 TEM、高分辨率 TEM 成像和拉曼分析对通过 3D 轴对称探针扫描在不同位置局部收集的所生产石墨烯样品的形态、质量、平均粒径和层数进行研究。收集到的信息对于等离子体反应器设计非常有价值。